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8.2L Carb Problems

J

JSK

New member
I'm new to the forum having just bought 31 Tiara with twin 1994 8.2L Merc carb inboards. I'm new to inboards having owned outboards all my life. I have done maintenance work on my car over the years so I've got some basic skill. The port engine seems to burn significantly more fuel then starboard (25%+-). It runs rich at cold start leaving a visible sheen on the water from the exhaust. Runs great after warm-up. Engine timing is set correctly, new spark plugs, cap, rotor. It has the stock Weber CFM carbs. Any ideas what he issue might be?

Also, does anyone have experience changing the raw water impellor on this engine? The raw water pump component is also the fuel pump. How difficult is it to remove the assembly, replace impellor and re-install?

Thanks, John
 
It runs rich at cold start leaving a visible sheen on the water...
Click to expand...
Choke worn out...opening late? Look into the carb, throttle open wide, engine warm but off to see if fuel is leaking into manifold. Look for fuel in the semi-clear tube running from fuel pump to carb top.
 
JSK said:
I'm new to the forum having just bought 31 Tiara with twin 1994 8.2L Merc carb inboards. I'm new to inboards having owned outboards all my life. I have done maintenance work on my car over the years so I've got some basic skill. The port engine seems to burn significantly more fuel then starboard (25%+-). It runs rich at cold start leaving a visible sheen on the water from the exhaust. Runs great after warm-up. Engine timing is set correctly, new spark plugs, cap, rotor. It has the stock Weber CFM carbs. Any ideas what he issue might be?

Also, does anyone have experience changing the raw water impellor on this engine? The raw water pump component is also the fuel pump. How difficult is it to remove the assembly, replace impellor and re-install?

Thanks, John
Click to expand...

Ayuh,.... Those Weber carbs are a carbon copy of the eldebrock performer carbs,..

Grab a carb kit, 'n rebuild it,... Guy is probably Right, pay attention to the choke,...

For the impeller, pull the Whole thing off, 'n swap it on the bench,...
Pay special attention to which hose, goes where,...
 
Guys,
Thanks for the tips. I'll check the choke this weekend. Not sure what you mean regarding the Clear tube running to the top of the carb. Should it have fuel in this line or does that indicate problem?
Thanks again,
 
Should it have fuel in this line or does that indicate problem?
Click to expand...
No fuel in it, if there is then the mechanical fuel pump diaphragm is leaking. Not applicable if the pump is electric.
 
No fuel was in the return line. I noticed the spark arresters were very dirty so I cleaned them well with carb cleaner and compressed air. The engine starts much better cold and smokes less during and after warm-up. Less un-burnt fuel on the water too during warm-up. I filled the fuel tanks and the offending engine only took 2 more gallons then the other side, 45 and 43 gallons respectively. I'll keep an eye on it but I think problem solved. Thanks for the help.
 
The electric choke bi-metal coiled spring is designed to open quickly from the heat of the electric element. If it is burned out the choke will open slower and thereby the engine will consume more fuel when cold. A simple test of the element is easy...after the engine has been running for 5 mins. feel the choke housing...if it is warm to touch the element is still working.
If it feels cold the element cold be burned out or the 12 volt source for it may have failed.
 
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